The new fall TV season doesn't roll out until next week, but NBC Entertainment Chairman Bob Greenblatt has already received a big vote of confidence from his bosses.

NBCUniversal on Friday extended Greenblatt's employment contract through 2017 even though his current deal wasn't set to expire until the end of 2014. Greenblatt joined NBC in 2011.

NBCUniversal Chief Executive Steve Burke has been high on Greenblatt's development for the upcoming TV season. Burke and executives at NBCUniversal parent Comcast Corp. hope one or more new prime-time shows will catch fire, which would help attract new advertising dollars to the broadcast network.

For the last two years, Greenblatt has been trying plug holes and halt the downward spiral in ratings that began with NBC's 2004-05 television season. Last year, the network began to stabilize its performance in prime time, which helped it negotiate higher rates from advertisers during the commercial sales auction that wrapped up in July.

NBC ended last regular season in third place among the broadcast networks in the key demographic of viewers aged 18 to 49. It is the least profitable of the major broadcast networks, making more than $500 million less than competitors ABC, CBS and Fox.

Among the new shows Greenblatt is introducing is crime drama "The Blacklist," starring James Spader. The network also is trying to revamp its Thursday night lineup with a family sitcom starring Michael J. Fox, "The Michael J. Fox Show," and a comedy starring Sean Hayes called "Sean Saves the World."

In addition, NBC is gambling on a high-profile production in December of "The Sound of Music," performed by a cast of Broadway stars. But its riskiest move is scheduled for February, when Jay Leno is expected to retire to make way for Jimmy Fallon to take over "The Tonight Show," which will move to New York from Burbank.